Process for casting metal



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H. A. MYERS PROCESS FOR CASTING METAL Filed Aug. 4, 1919 8 Sheets-Sheet1 15%? "Z ens Nova 11, 1924- 1,515,163

H. A. MYERS PROCESS'FOR CASTING METAL Filed Aug. 4, 1919. a Sheets-Shet2 Nov. 11, 1924.

A. MYERS PROCESS FOR CASTING METAL 1919 8 Sheets-Sheet 5 Filed Aug. 4

H. A. MYERS PROCESS FOR CASTING METAL Filed Aug. 4, 1919 8 Sheets-Sheet4 Nov. 11", 1924. 7 ,515,163..

H- 'A. MYERS I PROCESS FOR CASTING METAL Fi l ed Aug. 4;, i919 aSheets-Sheet 5 NOV, 11

H. A. MYERS PROCESS FOR CASTING METAL 8 Sheets-Sheet 6 Filed Aug. 4,1919 lirilllillilllllll x Nov 11, 1924. i 1,515,163

H. A..'MYER$ PROCESS FOR CASTING METAL Filed Aug. 4, 1919 8 Sheets-Sheet'7' Jaye/0Z5) H. A. MYERS v PROCESS FOR CASTING METAL 191-9 8Sheets-Sheet 8 Filed Aug. 4

Patented Nov. 11, 1924.

stares HUBERT A. MYERS, OF TOLEDO, OHIO, ASSIGNOR TO THE HUBERT A.IMIYERS COMPANY,

. OF TOLEDO, OHIO, A CORPORATION OF OHIO.

PROCESS FOR CASTING METAL.

Application filed August 4, 1919. Serial No. 315,054.

To all whom it may concern: 1

Be it known that I, HUBERT A. MYERS, a citizen of the United States ofAmerica, and a resident of Toledo, Ohio, have invented a certain new anduseful Improvement in Processes for Casting Metal, of which thefollowing is a specification.

This invention relates to the production of die castings. In themanufacture of die castings the mold for making the castings is in thenature of a die or a plurality of cooperating dies, and is used againand again, as distinguished from an ordinary mold whichis destroyedafter the molten metal has cooled, so that a new mold is necessary foreach casting operation.

Generally stated, therefore, the object of.

the invention is to provide an improved process or method and anapparatus for making die castings in a. rapid and economical andsatisfactory manner.

A special object is to provide an improved method and means for diecasting the metal in a manner that will not injure the casting, and in away that will leave each casting, even when-made from iron or steel,with a smooth outer surface and with the hardness or softness of themetal, whichever may be desired, of the required character.

Another object of the invention is to provide a novel and improved moldto which the molten metal will not stickor adhere during the die castingoperation, and from which the casting, when sufficiently cool, can bedischarged easily in the required manner.

It is also an object to provide certain details and features ofconstructionand combinations tending to increase the general efiiciencyand the desirability of a die casting apparatus and process of thisparticular character.

To these and other useful ends the invention consists in mattershereinafter set forth and claimed and shown in the accompanyingdrawings, in which Fig. 1 is a plan of a die casting apparatus embodyingthe principles of the invention.

Fig. 2 is a longitudinal vertical section of said apparatus.

Fig. 3 is an enlarged plan of the left %and port-ion of the apparatusshown in l ig. i is an enlarged plan of a portion of the apparatus shownat the right in Fig. 1.

Fig. 5 is a vertical lon itudinal section of the apparatus shown in ig.3.

Fig. 6 is an enlarged vertical section of the portion of the apparatusshown at the right in Fig. 1.

igs. 7 and 8 are detail views showing casting machine for receiving themolten metal, having cooperating dies forming the molds. And, fourth, amachine for receiving the castings. from the casting machine, which maybe called a cooling machine. The different machines will be described inthe order mentioned.

Ta; ladle.

This machine, it will be seen, comprises a hollow metal body 1 having arefractory or heat-resisting llning 2, and provided with legs 3 tosupport it in any suitably elevated position. A receptacle 4 having asuitable lining 5 has its bottom provided with a downwardly. extendingspindle 6 to which is fixed a worm wheel 7 whereby the ladle orreceptacle 4 may be rotated about a vertical axis. worm 8 on the shaft9, which latter is operated by an electric motor 10, or in any suitablemanner. Bunsen burners 11, of any suitable character, are provided, inthe manner shown, to keep the receptacle 4 hot, thereby to maintain themetal in a molten condition. A cover 12 of any suitable heatresistingmaterial isapplied to the top of the receptacle 1, and is provided withan opening 13 through which the molten metal is poured from the spout14, and with another opening 15 through which the metal is removed, aswill hereinafter more fully This is accomplished by a arms 18, isarranged adjacent the plate 16,

in the manner shown, and is rotated, by any suitable means, so that thearms 18 will force the slag along the plate 16 and cause it to dischargefrom the end of the plate,

' which latter slightly overhangs the rotary receptacle. The plate 16,it will be seen, has its outer edge provided with a flange 19 whichkeeps the slag from falling off, and

the receptacle 4 rotates in a direction to bring the slag against thefront edge 20 of the plate, and said wheel thenf; throws the slag oflfrom the end 21 of said plate. Thus the rotation of the ladle not onlymakes it possible to always present a fresh surface of the metal to theorifice 15, but also enables the skimming device to remove the slag.

The filling machine.

This machine comprises a pedestal or base 22 having an upright hollowpost 23 mounted thereon. Within this post is a vertically disposed shaft24, to the lower end of which is fixed a worm wheel 25, the latter beingengaged by the worm 26 on the shaft 27, which latter is preferablyoperated by a motor 28 of any suitable character. A head 29 is connectedby a spline 30 with the upper end of said shaft 24, and hollow armsforming radially disposed and oppositely arranged guides 31 which areremovably secured in place by screws 32, and which rotate with the head29, are also provided whereby these guides 31 are adapted to slide upand down on the shaft 24, by reason of the spline 30, during theoperation of the machine. The post 23 is provided with a cam 33, androllers 34 are suitably mounted in the base of the rotary structure,these rollers traveling on the cam 33, so that when the rollers engagethe high portions of the cam the rotary structure is raised, and whenthe rollers travel into the low portions of the cam the rotary structureis then lowered. Bolts or screws 35 are emploved for removablyconnecting the rotary structure to the head 29. so that the structurecan be removed and taken apart. Each guide 31 has a slide 36 therein.Furthermore, the screws 32 serve as vertical pivots, so that the arms orguides 31 are adapted to swing about vertical axes provided by thesepivots.

A cam plate 37 is mounted onthe post 23, and is provided in its uppersurface with an outer cam groove 38 to engage rollers or projections 39carried by the slides 36, and

the shape of this capo groove, as shown in Figs. 11 and 12, is such thattheslides 36 are moved endwise in the desired manner head 44 at theouter end thereof containing a depending nozzle 45, which latter ispreferably made of porcelain or some other material which will not onlyresist the heat but also the corrosive action of the molten metal.nozzle, adapted to reciprocate vertically therein. These plungers areconnected with pistons 47 in the cylinders 48, the latter beingsupported by uprights 49 carried by the heads 44, whereby verticalreciprocation of these pistons in their cylinders causes a similarreciprocation on the part of the plungers. Each plunger preferablyslides up and down in a stufling box 50 suitably provided in the upperportion of the nozzle. Fluid pressure of any suitable character issupplied to the upper and lower ends of the cylinders 48 through pipes51 and 52, suitably connected with a source of pressure. Said pipes areprovided with valves 53 and 54, of any suitable character, to controlthe fluid pressure, and said valves are operated by vertically disposedrods 55 connected thereto, these rods having their lower ends connectedto levers 56 which are suitably .pivoted at 57 to tilt about horizontalaxes.

the pivotal support for each lever being carried by the rotarystructure, and being of any suitable character. A cam 58, of anysuitable form or shape, is mounted on the A plunger 46 is provided foreach receptacle 1, previously described, to engage one end of the lever56, thereby to move the rod 55 upwardly, thus automatically controllingthe valves. When said rod is moved upwardly, valve 53 is closed to shutoff the fluid pressure to the top of the cylinder 48, and to at the sametime allow the fluid pressure to escapefrom the top of the cylinderthrough the port 59 at the top of said valve. At the same time the valve54 is opened to admit fluid pressure to the lower end of the cylinder48. so that the piston 47'and the plunger 46 will be moved upwardly. Thevalve 54 has a similar port 60 which is open to exhaust the fluidpressure from the cylinder when the piston moves downwardly therein, aswill more fully hereafter appear, it being understood that the valvesare constructed for this purpose in any suitable, known or approvedmanner.

The casting machine.

- disposed centrally of said pgst. The lower end of said shaft has astep bearing 63, of

suitable character, and this step bearing is disposed a suitabledistance from the similar step bearing 64 of the shaft 24 previouslydescribed. A head 65 is sebured to the upper end of the shaft 62, and aworm wheel 66 is secured to the lower end of said shaft, this wheelbeing engaged by the worm 67 on the shaft 27 previously described. Arotary turntable 69 is secured to the head 65, and arranged to rotate onthe shoulder 69 formed on the center post. A cam plate 7 0 having a camgroove 71 formed therein is secured on the post 61, in any suitablemanner, below the rotary turntable. The dies 72 and 73 are secured inpairs to the turntable. each pair forming a complete mold, and thesemolds are arranged in a circular row, in the manner shown, and areadapted to receive the molten metal to form the castings. The outer dies7 3 are pivotally mounted on the arms 74 which project from theturntable, so that trunnion bearings 75 are formed about which the outerdies are adapted to tilt. The inner dies 72 are each secured to ahorizontally reciprocating and radially arranged rod 76, each rodreciprocating in a guide 77 suitably provided on the turn-table. Theinner ends of these rods are provided with rollers or projections 78 toengage the cam groove 71 previously men tioned, this groove being of ashape to cause the rods 76 to reciprocate endwise in their guides duringthe rotation of the turn-table. Links 79 are pivoted at 80 to the outerdies 73, above the trunnion bearings 75, and these links have slots 81for engaging the pins or similar means 82 on the sides of the inner dies72, whereby inward displacement of any inner die 72 will first leave theouter die 7 3 in upright position, and will then, when the pin 82reaches the end of the slot 81, pull the outer die into a horizontalposition with its inner face downward, as shown in Fig. 19, thereby todischarge the casting. The two dies have their inner faces formed withcavities to receive the molten metal, and the tops of the dies, whenheld together, provide openings 83 to receive the nozzles 45,alternately, of course, after each nozzle has sucked up a supply ofmolten metal from the ladle, and has been carried around to a positionwhere it can then discharge the molten metal into one of the molds, asshown in Fig 5, and as will hereinafter more fully appear. Each moldcarries a cam 84 for engaging the levers 56, thereby to pull the rods 55downward, so that the valves 53 and 54 are controlled to cause the fluidpressure to "force each piston 47 downward when it arrives over one ofthe molds, and as soon as the corresponding nozzle below is in positionto discharge the molten metal into the mold. The molds are provided withburners 85 of any suitable character, connected in any suitable mannerwith a source of gas pressure, to direct flames against the dies.thereby to heat the. latter to the required temperature, and to maintainthem at such a temperature, so that the molten metal will not bechilled. Also, as shown, nozzles 86 are provided at the other side ofeach mold to direct jets of air against the dies to cool them in casethey become too hot, the idea being to keep the molds at a temperaturewhich will prevent chilling of the molten metal, so that castings of therequired softness or character will be obtained, but at the same timeinsure sufl'icient cooling of the molten metal to insure a propercondition for the casting when it arrives at the point of discharge, sothat when discharged the casting will have been cooled suificiently tokeep it from losing its shape or from being distorted whendropped intothe means provided for receiving the castings. A valve 87 controls thesupply of gas to each pair of burners and this valve is controlledthermostatically, as by an electro-thermal device, so that the flame isautomatically regulated to insure the required temperature of each mold.It will be understood that said thermostatic device may be of anysuitable char acter, such as any of those employed for similar purposes,or the device may involve an instrument ofany suitable character, and isin any event governed by the heat of the mold. A similar valve 88controls the supply of air to each. pair of nozzles 86 and isautomatically controlled by a similar thermostatic device or by anelectro-thermal device governed by the heat of the mold. whereby themolds are prevented from becoming either too hot or too cold, and areautomatically maintained at agiven temperature or at the desiredtemperature. Thus there is practically no shrinkage of the molds betweenfillings or pourings. as successive castings are made without reducingthe temperature of the molds below the point necessary for each filling,and necessary for each casting.

The cooling machine.

ployed for annealing purposes. As shown,

this machine comprises an endless belt 89 provided with guards 9O spacedapart to ill-3 form a trough for receiving the castings, the belt beingsuitably mounted and arranged for that purpose. A trough or pit 91 isprovided in a suitable manner to contain ground or powdered mica orother material into which the castings can be dropped to prevent themetal from being hardened by the cooling process, so that the propertemper for the metal will be insured. An endless belt 9:2 is arranged totravel over rotary members 93. 9st. 95. 96, 97 and 98, and is providedwith cleats or scrapers 99 adapted to carry the mica upward anddischarge it onto the plate or chute 100. so that the mica or othermaterial will be discharged into the trough formed between the plates orguards 90 previously mentioned. In this way the castings are received inthe soft mica or other material. and are car ried along and allowed tocool without giving the metal too much hardness or temper, so thatcomparatively soft metal castings are produced, and these castings andthe mica are discharged onto the shaker or rocker grate 101, the latterbeing operated in any suitable manner to shake the mica or othermaterial away from the castings. leaving the latter clean and free toslide off from the end of the grate.

The operation.

From the foregoing it will be seen that while one nozzle 45 is suckingup molten metal from the rotary ladle or receptacle 4, the rotarystructure 31, 36 etc., having been lowered by the cam 33 for thatpurpose, the other nozzle 45 is discharging its contents into one of themolds. The filling machine revolves in the direction of the arrows.shown in Figs. 11 and 12, and the casting machine revolves in theopposite direction. The cam grooves 38 and 42 are of such shape, it willbe seen. that the nozzle 45 which is sucking up the molten metal fromthe ladle remains stationary in the opening 15 while the other nozzle 45is discharging and traveling along with one of the molds. Fig. 12 showsthe relative positions of the two nozzles when one begins to take up acharge and the other begins to discharge, and Fig. 11 shows the mannerin which the nozzle which is being filled has remained stationary.notwithstanding the revolving movement of the machine. while the othernozzle has traveled a distance with the mold into which it wasdischarging. the molten metal. As soon as one nozzle is empty, the twoheads then rise, being lifted by the action of the cam 33, and the emptynozzle re- "olves until it is over' the opening 15, and the full nozzlerevolves until it is over one of the molds. and then the two heads 44are again lowered and the operation justdescribed is repeated. Thisoccurs for each mold of the casting machine, the worm gear- 'ing bywhich the filling machine and the casting machine are operated being sotimed that the molds are filled successively, and the cam groove 71causes the molds to be successively opened, thereby discharging thecastings in rapid succession into the cooling machine. Referring toFigs. 9 and 10, it will be seen that each die comprises a rectangularframe having a. removable top plate 102, and the interior body portion103 of each die, which is formed to receive the molten metal, is easilyremoved from said frame by removing said top plate. The die proper 103can be made of any suitable material, but is preferably made fromporcelain clay. The clay, in powdered form, such as the commercialporcelain clay em ployed for various purposes, is prepared in the usualmanner and baked until it has the desired hardness, such as theporcelain employed in various articles of manufacture, or it may beeither softer or harder. The dies formed in this way, and from thismaterial or other refractory heat resisting material, can be kept veryhot, at red heat if necessary, and will resist the heat of the moltenmetal and will prevent too sudden chilling of the metal, and thecastings will be freely discharged with clean and glossy or smoothsurfaces. In this way die castings are produced rapidly and in a mannerthat subjects each mold to practically continuous use and in a way thatnot only does not require cooling means to keep the molds cool, or anycooling of the mold be fore the casting is discharged therefrom, as insome previous practice, but in a manner that actually insures beneficialresults from the keeping of the molds at high temperature before andduring the formation of the casting, so tha-t'never at any time is themold below its working temperature while in contact with the metal. thecasting being expelled from the mold while the dies are still at hightemperature and while the metal is still so hot that soft means arerequired to receive the castings and keep them from being distorted andfrom cooling too fast: and this, as stated, prevents sudden chilling ofthe metal and insures against too abrupt solidifying of the moltenmetal, resulting in the production of die castings of desirably softmetal, instead of metal which is hardened or tempered. so to speak,until it is too hard and too brittle to be satisfactory for manypurposes. Ordinarily cast iron. when produced in the form of diecastings. is too hard and too brittle. but the method herein describedaffords a way in which to convert molten iron or steel or any othermetal into die castings which will have the required softness, or whichwill be of a malleable character. so to speak. much like the ordinarymalleable iron castings. But this is accomplished directly, it

will be seen, by rapid die casting operations, so that the finishedproduct comes directly from the cooling machine which is in the natureof a leer, and which receives the castings directly from the moldingmachine, so that the desirable object of producing com- )aratively softor malleable iron castings by .he use of dies, instead of by usingordinary sand molds or similar means, is accomp-lished in a satisfactoryand efiicient manner. Also, as a matter of further and specialimprovement, it is found that an admixture of graphite with theporcelain clay, in the making of the molds, has a beneficial result.This produces a mixture which is easily worked, and which can be given asmooth surface. In addition, it is found that the metal is still furtherprevented from sticking to the mold. In the making of die castings ofmetal, it has been the practice, more or less to keep the molds or diescool. as they were ordinarilv made of material which would not stand thehigh temperature or which would produce injurious results if allowed tobecome highly heated. As explained, however, the preheating of themolds, in the manner described, and the maintenance of the molds at ahigh temperature until after the discharge of the castings, which issubstantially different from previous practice, serves to preventchilling of the metal from which castings are to be made, and results iniron or metal castings of a character previously impossible orimpracticable with the die casting methods heretofore employed. In otherwords, the

invention contemplates the practical reversal of the previous practiceand ideas on the subject, and involves the heating of the molds to ahigh temperature, and the allowing of the molds to remain at thetemperature which they would naturally acquire from continuous use, fromthe heat of the molten metal, or even a higher temperature, or suchtemperature as is necessary to prevent sudden chilling and consequenthardening of the cast metal, which would make the castings too hard andbrittle to suitable for certain purposes. Of course, after the machinehas been in operation for a while, the heat of the molten metal may besuflicient to keepthe molds at the rapiire-d temperature, if thecastingoperations are close enough together but if the casting machinedoes not revolve rapidly enough to keep each mold 1n almost constantuse, then the heating attachment for each mold will automatically bebrought into operation by the thermostatic control previously mentioned,thereby to keep each mold at the required temperature. When the dies ofthe molds are thus kept heated, from one casting operation to the next,they are not subject to alternate expanslon and contraction, such aswould result from cooling the mold aftereach operation, and in this wayand because of the materials employed a reasonably or comparatively longlife is' ensured for the as in a cupola or other instrumentality, and

is poured into the ladle fast enough and in sufficient quantity to keepthe die casting or molding machine constantly supplied, so

that each mold will receive its charge or sup- I ply of molten metalfrom the filling machine. whereby each mold will produce a casting foreach revolution of the machine. If graphite is used in the preparationand construct-ion of the'molds, or of the dies for the molds, themixture may be formed from one part-of graphite and three parts ofporcelain, as this is found to give good results. The noz zles 45 of thefilling machine can be composed of the same substance if desired, and inthis connection it will be seen that the molten metal is drawn up fromthe receptacle 4 by a vacuum, inasmuch as the suction produced by theupward movement of the plungers 4,6 is the result of the vacuum formedinside of each nozzle. In the making of the dies for the molds, theporcelain clay can be mixed with fine sawdust, or with wheat flour.preferabl browning the latter first, and after the dies are fired orbaked they are then porous. After this, the dies can be dropped intoboiling oil and graphite, which will drive the graphite into the dies.In baking or firing the dies a high temperature is used, but not highenough to render the porcelain clay vitreous, the temperature being keptbelow this point, so that preferably each die when finished is justabout hard enough to file or work easily. If this method is employed,about 15% of flour or fine sawdust can be employed, but this can bevaried according to the requirements and the particular results desired.The temperature employed for baking or firing the molds can be varied,but approximately 2000 Fahrenheit has been found to give satisfactoryresults. which is, of course, considerably belowthe temperaturenecessary for vitri ing porcelain clay of this kind. If the ies are toohard, or are vitrified, they are liable to crack easily when the moldsreceive the molten metal; but when made soft, as explained, they canbeheated quicker without danger ofcracking and are of such character thatthey can be filed or cut or otherwise worked, but are not too soft tostand up in use. In practicing the process, the molds are raised to atemperature sutficient to prevent them from,

say about 1 1200 to 1400 Fahrenheit, alv hough it is found that they canbe made to work. at a, muchlower temperature. Thus cracking or chillingthe iron or other metal,

at no time does the molten metal encounter a cool mold, or die of lowtemperature, and at no time are the dies in contact with completelycooled metal, as each previously heat ed mold remains at almost aneventemperature during its use and receives hot metal and discharges hotmetal therefrom during each casting operation. Also, if desired, thefaces of the dies, constituting the interior surfaces of the molds, canbe sprayed with black lead or graphite after each mold has been openedto discharge the casting, and before the mold is closed. For example,this can be done by means of a nozzle 104, of any suitable character,adapted to blow the lead or graphite into each mold at a certain pointin the circular path of travel of the molds shown in Fig. 1, thisoperation occurring just after the cam groove 71 has brought the pivotedor swiveled section of the mold into vertical position. but before thetwo sections of the mold are brought tightly together, and while thereis still space between the two sections or dies to permit the entrancebetween them of said nozzle, or of the jet from said nozzle, dependingupon the arrangement and mode of operation desired for said nozzle. Thisnozzle, of course, can be operated or controlled in any suitable ordesired manner, and may be entirely automatic if desired (by means ofoperating and controlling mechanism not shown), or .it may be insertedby hand if such is necessary or desirable. In any event, the interior ofeach mold is given a coating of black lead or graphite before itreceives the molten metal, which tends to prevent the casting fromsticking to the mold.

The thermostatic control of the valves 87 and 88 may be of any suitablecharacter, as explained, and as indicated diagrammatically in Fig. 3,in. which the electric circuit is shown for controlling theelectro-magnet (not shown), which efiects the opening and closing of thevalve 87 and which is in turn controlled by the thermostatic device notshown) associated with the mold. The electro-magnetic mechanism foroperating the valve 88 of each mold is, of course, provided with acircuit similar to the circuit 105, and is controlled by a thermostaticdevice associated with the mold, whereby these two valves areautomatically controlled by the temperature of the mold. As thesethermostatlc devices and automatically operated valves are old and wellknown, such as those made by Brown Instrument Company of Chlca-go.Illinois, nofurther illustration or description thereof is necessary.

Any suitable means, of course, may be employed for agitating the shakergrate 101 to separate the mica or other soft material from the castings.'Ihese castings, as previously stated, produced from dies or moldscomposed of porcelain, have smooth and emma glossy surfaces, and thedesired results in this respect are still further insured by theintroduction of graphite into the pores or voids of the porcelain, whenthe latter is fired or baked, in the form of a mixture of of the castingwhen it is discharged fronr the mold, and the cooling of thecastings.throughout the process, is so gradual that the metal is not hardened.The mold with its highlyheated dies discharges its casting and is thenimmediately brought back into use while thus in highly heated condition.Practically, therefore, each mold is maintained at a high temperatureduring and between the successive casting operations per formed therein,so that each casting is discharged from a mold that is still in highlyheated condition. Thus the metal is received in a hot mold and isthereafter discharged therefrom before very much cooling thereof hastaken place. Preferably, as explained, the mold remains at hightemperature from one casting operation to the next. received in a highlyheated mold and is thereafter discharged while the mold is still hot,and perhaps hotter, thus ensuring a reasonably long life for the dies ofthe mold and a malleable iron or other metal casting of the desiredcharcter.

'Ihe pre -heating of the molds is important, of course, inasmuch as inaccordance withthe invention the substance from which the dies are madeis selected with special reference to its capacity or adaptability toserve its purpose better when heated than when cool, so that the diesserve their intended purpose, in every respect, much better whenmaintained at high temperature while alternately empty and fullthat isto say, while each mold is alternately carrying a casting and returningempty to the point where it will receive another charge of molten metal.In the production of successive die castings from the same mold, or froma series of molds, the highest efliciency is obtained, of course, whenthe machine is operated as rapidly as possible, so that each mold isfilled and caused to discharge its casting, and is then refilled in theshortest possible space of time. Under such circumstances. therefore,the heat of the molten metal itself is calculated to maintain the moldsat high temperature, and while they might be cooled or kept below a toohigh In any event, though, the metal is V temperature, with the diesmade of any substance which works or functions better when cool thanwhen highly heated. it is the bet-' ter plan to allow the molds tobecome as highly heated as they will. and to allow them to remain atsuch temperature. and for this reason a substance is selected for thedies which will accord with this theory and which will not onlywithstand the high temperature but which will actually work better andproduce better results when maintained at a high temperature.

Features not claimed in this application will be claimed in divisionalapplications to be filed in accordance with the requirements of thePatent Office.

What I claim as my invention is 1. The process of casting metal toproduce die-castings from the same mold, which. comprises themaintaining of the casting means at high temperature before and afterreceiving the first charge of molten metal therein, thereby to preventsudden chilling and to fast cooling of the molten metal. as well assudden heating of the mold. cooling the casting without cooling the moldbelow the temperature necessary for the formation of the next casting,and retaining the mold in heated condition to receive another charge ofmolten metal therein, discharging each casting while it and the mold arestill in highly heated condition. thus maintaining the mold continuouslyat high temperature while alternately empty and full, in whichporcelainat high temperature is employed as the. casting means in direct contactwith the metal to produce a casting having a smooth surface, theporcelain at said high temperature producing this elfect and allowingthe metal to separate readily therefrom without sticking thereto.

2. The process of casting metal to produce successive die-castings fromthe same mold, which comprises the maintaining of the casting means athigh temperature before and after receiving the first charge of moltenmetal therein. thereby to prevent sudden chilling and too fast coolingof the molten metal, as well as sudden heating of the mold, cooling thecasting without cooling the mold below the temperature necessary for theformation of the next casting, and retaining the mold in heatedcondition to receive another charge of molten metal therein, dischargingeach casting while it and the mold are still in highly heated condition,thus maintaining the mold continuously at high temperature whilealternately empty and full, in which porcelain at high temperature isemployed as the casting means in direct contact with the metal toproduce a casting having a smooth surface, the porcelain at saidhightemperture producing this effect and allowing the metal to separatereadily therefrom without sticking thereto, having'said porcelaincharacterized by an admixture therewith of a suflic-ient quantity ofgraphite to prevent the metal from sticking to the mold.

3. The process of casting metal to produce successive die-castings fromthe same mold, which comprises the receiving of the charge of moltenmetal for the first casting in high temperature forming means, .coolingthe casting without cooling the mold below the temperature necessary forthe next casting, discharging the casting from said means while both arestill in highly heated condition. and retaining said means inheatedcondition for the next charge, thus maintaining said means at hightemperature while. alternately empty and full. in which both artificialheat and the heat of the metal are utilized to heat the forming means.

4. The process of casting metal to produce successive die-castings fromthe same mold. which comprises the receiving of the charge of moltenmetal for the first casting in high temperature forming means, coolingthe casting without cooling the mold below the temperature necessary forthe next casting, discharging the casting from said means while both arestill in highly heated condition, and retaining said means in heatedcondit on for the next charge. thus maintaining said means at hightemperature while alternately empty and full, comprising the use of somerefractory non-metallic substance which is previously heated towithstand the sudden heat of the molten metal and which is thus employedin direct contact with the metal in said forming means to prevent ad-vhesion of the metal thereto and for thus ensuring a smooth surface forthe casting.

5. The process of casting metal to produce successive die-castings fromthe same mold. which comprises the gradual cooling and solidification ofthe first charge of liquified metal, into the desired form, by the useof previously heated forming means, not adapted when cool to withstandthe sudden heat of the molten metal, without cooling the castingoperations occurring so close to-' gether that the dies remain at hightemperature from each operation to the next, comprising the heating ofthe mold before receiving the first charge of molten metal therein, to.prevent injury thereto and to the casting as well, without cooling themold below the t mperature necessary for the next casting, and expellingeach castmg while- I 1,515, we

still at high temperature and when solidified only enough to ensureagainst distortion thereof, in which artificial heat is employed toraise the temperature of the dies before the mold receives the firstcharge of metal, to guard against injury to the dies and preventchilling of the metal, and in which the dies thus preliminarily heatedremain at high temperature until after the casting is dischargedtherefrom.

7 The process of casting metal to make successive die-castings from thesame mold, comprising the use of a substance for the dies of said mold,which substance is a nonmetallic material which is better for itspurpose when maintained at high temperature than if allowed to remaincool, heating the mold before it receives the charge of molten metal,filling the mold while maintained at high temperature to prevent injurythereof, and to prevent injury of the casting, and forming the castingin a manner to prevent any disturbance of the molten metal after itenters the mold, allowing the casting to cool without cooling the moldbelow the temperature required for the formation of the next casting,releasing the casting while it and the mold are still at hightemperature, and retaining the mold in heated condition to receive eachsucceeding charge therein, the high temperature being not only to ensuredie-castings-of the desired character, having smooth surfaces, but alsoto protect the dies against injury from too sudden heating by the hotmetal, said substance being porcelain and said metal being iron.

8. The process of casting metal to make successive die-castings from thesame mold, comprising the use of a substance for the dies of said mold,which substance is a nonmetallic material which is better for itspurpose when maintained at high temperature than if allowed to remaincool, heating the mold before it receives the charge of molten metal,filling the mold while maintained at high temperature to prevent injurythereof, and to prevent injury of the casting, and forming the castingin a manner to prevent any disturbance of the molten metal after itenters the mold, allowing the casting to cool without cooling the moldbelow the temperature required for the formation of the next casting,releasing the casting while it and the mold are still at hightemperature, and

retaining the mold in heated condition to receive each succeeding chargetherein, the high temperature being not only to ensure die-castings ofthe desired character, having smooth surfaces, but also to protect thedies against injury from too sudden heating by the hot metal, includingthe use of both artificial heat and the heat of the molten metal tomaintain the mold at high temperature while thus alternately empty andfull.

HlUlBlERT A. MYERS.

